The present invention relates to gas circuit breakers, and particularly to the improvement in an operating force transmitting mechanism for transmitting an operating force to a breaker unit.
A gas circuit breaker used in a extra-high voltage system is provided with a closing resistor device for restricting a surge voltage upon closing. This closing resistor device is electrically connected in parallel with a main interrupting unit, and formed of a series connection of resistors and resistor contacts. The resistor contacts are closed before the main contacts are closed, to permit the resistors to be placed in a circuit. That is, the resistor contacts are "preinserted" to restrict a surge voltage upon closing the circuit and the resistor contacts are opened before the contact is opened.
To easily adjust such a operating characteristic as required in the closing resistor device, the main interrupting unit and a driving unit are combined into one common unit to open and close the resistance contacts mechanically. For this, a mechanism for controlling the resistor contacts is branched from part of the operating force transmitting mechanism which connects moving contact of the main interrupting unit and the operating device.
The gas circuit breakers with and without the closing resistor device have each hitherto been designed and manufactured separately. In common gas circuit breakers, however, the number of series-connected interrupting units of the same structure are increased for higher voltages used. Therefore, if the circuit breaker unit can be standardized, irrespective of whether it has the closing resistor device or not, it will be very advantageous in design and manufacture.